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This study aims to simulate and test the performance of a transmitting and receiving capacitive micro-machined ultrasonic transducer (CMUT). Aimed at detecting demand of the CMUT, a matched integrated adjustment circuit was designed through analyzing processing methods of transducer’s weak echo signal.

Based on the analysis of CMUT array structure and work principle, the CMUT units are designed and the dynamic performance analysis of SIMULINK is given according to the demand of underwater detecting. A transceiver isolation circuit is used to make transmission mode and receiving mode separate. A detection circuit is designed based on the transimpedance amplifier to achieve extraction of high-frequency and weak signal.

Through experimentation, the effectiveness of the CMUT performance simulation and the transceiver integrated adjustment circuit were verified. In addition, the test showed that CMUT with 400 kHz frequency has wider bandwidth and better dynamic characteristics than other similar transducers.

This paper provides a theoretical basis and design reference for the development and application of CMUT technology.

This study aims to examine factors affecting Chinese adolescents’ purchase intention for local brands; this study focuses on the effects of perceived social status value and materialistic values.

A theoretical model relating perceived social status value of brands to purchase intention, including materialistic values as a moderator, was developed and tested, using a sample of 587 Chinese adolescent respondents. Another experimental study examined the variability of the moderation of materialistic values across different levels of peer pressure in a product usage occasion.

Perceived social status value associated with local and foreign brands significantly influences purchase intention for local brands. Moreover, influence of perceived social status value of local versus foreign brands on local brand purchase intention is greater for materialistic adolescents. Additionally, the moderation of materialistic values is found in a product usage occasion with high peer pressure, but not in an occasion with low peer pressure.

The findings show that perceived social status value associated with brands shapes purchase intention for local brands. The moderating effect of materialistic values is complex and suggests further research. The study’s scope is limited to Chinese adolescents.

The findings provide understanding of the drivers of purchase intention, and thus serve as a guideline for Chinese firms and foreign marketers seeking to enter the growing Chinese market, as well as consumer educators in China.

This study contributes to the limited empirical research into the factors shaping country-of-origin effects. Moreover, the findings suggest the need to consider the moderating role of materialistic values on purchase intention for local brands.

The purpose of this investigation was to study the function mechanisms of a corrosion inhibitor package used for martensitic stainless steel tubulars in acid solution at high temperatures.

The inhibition performance was evaluated by means of an acid corrosion test at high temperature and high pressure, and the functional mechanism of the inhibitor package at different temperatures was investigated using polarization curve and electrochemical impedance spectroscopy measurements.

The results showed that the corrosion inhibitor package chosen for high-temperature and high-pressure gas well applications was very suitable for use with 13Cr super martensitic stainless steel. At lower temperatures, the function mechanism of the corrosion inhibitor package was characterized as a type of negative catalytic effect. As the temperature was increased, the effect of the intensifier in the package became more significant and the function mechanism changed to be the geometric covering effect type.

This study has the important practical value for guiding the oil field to conduct reasonable screening and using the acidizing corrosion inhibitor for martensite stainless steel tubulars.

This chapter aims to investigate the research status and development of virtual community (VC) in China by a critique of library and information science (LIS) journal articles and to put forward future directions in virtual community for the researchers in our discipline. We used a multiple case of methods including bibliometric approaches (such as keyword frequency and co-word analysis) and a coding system to reveal several characteristics of the research status quo and trends. The results show that from 2000 to the present, VC-related research by LIS Chinese scholars has experienced rapid development with an increasing number of academic papers, authors, journals and institutions. However, LIS research is still at an early stage with the slow introduction of fundamental concepts and frameworks, lack of theoretical support, and organisations focused on empirical studies. VC-related research in China in recent years fully demonstrates its diversified attributes. Our study is limited to the analysis of academic journal literature published in mainland China while excluding dissertations and books, and publications in Hong Kong, Macao and Taiwan. Our classification system also needs to be more specific. Our findings have implications for researchers, students, journals and sponsors of Chinese LIS research related to virtual communities.

This paper aims to introduce a series of experimental results which are the extension of our previous novel observations (Xie et al., Soft Matter, 2011), which could be helpful for revealing the lubrication failure mechanism in bearings when they are exposed to an electrical environment.

An experimental apparatus where a ball was in contact with a glass disk coated with a semi-reflective chromium layer. A small volume of oil droplet was put into the microgap of the ball-disk contact. Then, a potential was applied onto the oil micropool formed by the droplet surrounding the contact region.

It has been found that destabilization of the low-conducting oil micropool around the contact region could be induced after applying a potential. Thin oil films could be drained out of the oil pool and spread on the tribopair surfaces, resulting in the depletion of the oil pool. When the applied potential was increased, the occurrence of spreading would be easier and its development would be more obvious. In contrast, the electrospreading behavior would be suppressed when the oil viscosity, contact load and oil pool size were increased. Thermocapillary force due to thermal effect as a result of the current flow near the oil pool border has been proposed as the main driving force for the spreading behavior. The influences of the operating parameters have been ascribed to the change of the electric current near the oil pool border as well as the corresponding variations in the temperature rise and the surface tension of the oil pool.

This is the first study to directly observe that the lubricant oil micropool around the contact region could deplete after applying a potential, potentially resulting in oil starvation in the contact region.

This paper describes the organic geochemical characteristics and their roles on barium enrichment in the No. 2 Coal from Huanglong Jurassic Coalfield, China. A total of 18 bench samples were taken from Huangling Mine 2. The average content of barium (3701 mg/kg) was about 23 times higher than that of common world coals. Terrestrial higher plants were the main coal-forming parent material. Relying on the parameters of OEP, Pr/Ph and so on, there is little correlation between organic geochemical characteristics and barium enrichment. Therefore, organic material has little influence on the process of coal-forming and the enrichment of barium.

The purpose of this study to investigate acetaminophen (ACT) degradation efficiencies by using ozone/persulfate oxidation process in a batch reactor. In addition, the effects of various parameters on the ACT removal efficiency toward pathway inference of ACT degradation were investigated.

The experiments were in the 2 L glass vessels. Ozone gas with flow rate at 70 L.h⁻¹ was produced by ozone generator. After the adjustment of the pH, various dosages of persulfate (1, 3, 5, 7 and 9 mmol.L⁻¹) were then added to the 500 mL ACT-containing solution with 150 mg.L⁻¹ of concentration. Afterward, ozone gas was diffused in glass vessels. The solution after reaction flowed into the storage tank for the detection. The investigated parameters included pH and the amount of ozone and persulfate addition. For comparison of the ACT degradation efficiency, ozone/persulfate, ozone and persulfate oxidation in reactor was carried out. The ACT concentration using a HPLC system equipped with 2998 PDA detector was determined at an absorbance of 242 nm.

ACT degradation percentage by using ozone or persulfate in the process were at 63.7% and 22.3%, respectively, whereas O₃/persulfate oxidation process achieved degradation percentage at 91.4% in 30 min. Degradation efficiency of ACT was affected by different parameter like pH and addition of ozone or persulfate, and highest degradation obtained when pH and concentrations of persulfate and ozone was 10 and 3 mmol.L⁻¹ and 60 mg.L⁻¹, respectively. O₃, OH^• and SO⁴⁻ were evidenced to be the radicals for degradation of ACT through direct and indirect oxidation. Gas chromatography–mass spectrometer analysis showed intermediates including N-(3,4-dihydroxyphenyl) formamide, hydroquinone, benzoic acid, 4-methylbenzene-1,2-diol, 4-aminophenol.

This study provided a simple and effective way for degradation of activated ACT as emerging contaminants from aqueous solution. This way was conducted to protect environment from one of the most important and abundant pharmaceutical and personal care product in aquatic environments.

There are two main innovations. One is that the novel process is performed successfully for pharmaceutical degradation. The other is that the optimized conditions are obtained. In addition, the effects of various parameters on the ACT removal efficiency toward pathway inference of ACT degradation were investigated.

Avant‐propos sous les auspices de l'Institut international de Coopération intellectuelle, paraissait en 1934 le t. I, consacré à l'Europe, du Guide international des Archives. Le questionnaire envoyé à tous les États européens comportait sous les points 4 et 6 les questions suivantes: ‘Existe‐t‐il un guide général pour les diverses catégories d'Archives ou des guides particuliers pour l'une ou l'autre d'entre elles?’ et ‘Existe‐t‐il des catalogues imprimés, des publications tant officielles que privées, susceptibles de constituer un instrument complet de référence pour tout ou partie importante des fonds d'archives?’ Les réponses des divers pays à ces questions, malgré leur caractère très inégal, ont fait du Guide international un bon instrument d'information générale sur les Archives. Malheureusement les circonstances ont empêché la publication du volume consacré aux États non européens, tandis que le temps qui s'écoulait tendait à rendre périmés les renseignements fournis sur les Archives européennes.

This study aims to test the impact of technological acceptance and trust toward e-government (TTEG), as well as perceived risk (PR) on the attitude toward using (AT) and the actual use (AU) of social media. This study also intends to examine the theoretical extension of the technology acceptance model by adding two variables, namely, TTEG and PR.

A total of 125 social media officers (SMO) were asked to fill out the questionnaire. To analyze the data, the researcher used the partial least square method using WarpPLS 6.0.

The findings of this study indicated that perceived ease of use (PEOU) has a positive and significant impact on perceived usefulness (PU). In addition, while PEOU, PU and TTEG influence AT significantly and positively, this research found that PR has no impact on AT. Furthermore, the authors also confirmed the positive and significant influence on AT, TTEG and AU. Meanwhile, PR has a significant and negative effect on AU.

This study first used non-probability sampling and as a consequence, that result could not be generalized. Another limitation is that this study used self-perceptual measures.

The study found that PR and TTEG are essential factors for increasing the use of social media by local government. Therefore, policymakers must create regional regulations to reduce risk and increase the trust of SMO. In addition, this study found that technology acceptance also had an effect on increasing activity on social media. For this reason, training in the use of social media is needed for SMO to increase the quality of content produced and citizen engagement.

Previous research has tried to look at the population’s characteristics, education levels, internet penetration and economic potential. Unfortunately, these studies did not highlight the capabilities of human resources, which in this case were the SMO.

This paper aims to obtain high mechanical and good tribological properties of epoxy resin-based coatings under dry friction conditions.

Bonded solid lubricant coatings containing Kevlar fibres were prepared by a spraying method. The friction and wear properties of the coatings were experimentally investigated with a face-to-face tribometre under dry friction conditions. Scanning electron microscopy, energy dispersive X-ray spectroscopy and 3D laser scanning technologies were used to characterise the tribological properties. The action mechanism of the Kevlar fibres on a solid lubricant transfer film was also analysed.

Adding Kevlar fibres can significantly improve the wear resistance of the coatings. When the Kevlar fibre content increases, the tribological properties of the coatings improve and then worsen. Superior properties are obtained with 0.03 g of Kevlar fibres. Appropriately increasing the load or speed is beneficial to the removal of the outer epoxy resin and the formation of a lubricant film. During friction, the solid lubricants wrapped in the epoxy resin accumulate on the surface to form a transfer film that shows a good self-lubricating performance. In the later friction stage, fatigue cracks occur on the solid lubricant film but cannot connect to one another because of the high wear resistance and the entanglement of the rod-like Kevlar fibres. Thus, no large-area film falls from the matrix, thereby ensuring the long-term functioning of solid lubricant coatings.

Epoxy resin-based solid lubricant coatings modified by Kevlar fibres were prepared, and their friction and wear properties were investigated. Their tribological mechanisms were also proposed. This work provided a basis for the analysis of the tribological properties and design of bonded solid lubricant coatings containing Kevlar fibres.